This is traditionally a day of great merry-making - the most well-known celebration being dancing around the maypole. The ribbon-plaiting dance we know today only began in the 19th century. Before that people used to dance in a ring around a large pole.
Another custom was for young men and women to go out on May Day Eve to collect may (hawthorn) blossom, flowers and blackthorn blossom. A young girl was elected Queen of the May and she presided over the May Day celebrations, which included mumming, morris and molly dances. Gingerbread was traditionally eaten on this day.
In Padstow in Cornwall two hobby horses dance through the streets. The Padstow May Carol is sung to welcome the summer.